Apparatus for making metallic receptacles



Jung 9, 1942. H. w. CLARK 2,285,903

' AiPARATUS FOR MAKING MgTALLIC RECEPTACLES Original Filed Nov. 7, 19:55I s Sheets-Sheet 1 I INVENTOR Harold W.1C/arK June 9, 1942. H. w. CLARKAPPARATUS FO R MAKING METALLIC RECEPTAGLES Original Filed Nov. 7, 1935 3Sheets-Sheet 2 it A 7 t j. T .,a

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H. w. CLARK APPARATUS FOR MAKING METALLIC RECEPTAGLES Original FiledNov. 7, 19:55

3 Sheets-Sheet 3 Ha m I JW F/a PK J Th Patented June 9, 1942 APPARATUSFOR MAKING METALLIC RECEPTACLE Harold W. Clark, Alliance, Ohio, assignorto The Steel Sanitary Company, Alliance, Ohio, a corporation of OhioOriginal application November 7, 1935, Serial No. 48,664, now Patent No.2,176,738, dated October Divided and 8, 1939, Serial No. 260,5

2 Claims.

This invention relates to the manufacture of metal receptacles and, inparticular, to receptacles made by the deep drawing of sheet steel. einvention will be disclosed as applied to the manufacture of bath tubsfrom sheet steel, but it will be apparent that other articles of likenature may be produced by the same method and apparatus, or with onlyslight modifications thereof. This application is a division of mycopending application, Serial No. 48,664, filed November 7, 1935, andnow Patent No. 2,176,738. Certain other subject matter disclosed in mysaid application Serial No. 48,664 and herein but not claimed in eitherthereof is disclosed and claimed in my copending applications SerialNos. 260,575 and 260,576, filed of even date herewith, and now maturedinto Patent Nos. 25,767 and 2,206,763, which are also divisions of mysaid copending application Serial No. 48,664.

While it has been proposed heretofore to make bath tubs by deep drawinga single steel sheet, so far' as I am aware, this result has never beenobtained commercially, at least on a practical basis. While it isprobably possible to draw a tub of sheet, the amount of waste involvedby the excessive scrap produced is so great as to rule out thispossibility commercially. It has also been proposed heretofore toproduce bath tubs by forming a plurality of tub sections and weldingthem together. This method has not met with Wide success because of thecost of welding the several joints and the problems introduced "bythenecessity for enameling thereover.

I have invented a method of making bath tubs by joining only two blanks,i. e., a drainend blank and a bell-end blank, by a circumferential seamor joint. This reduces the amount of welding necessary to a minimum.Theinvention also makes it possible to draw the two tub sections orblanks from single sheets without forming an excessive amount of scrap.In accordance with my invention,.I draw a steel sheet through a suitablyshaped die ring by means of a punch press and restrain the flow of themetal adjacent the edge of the sheet over the draw ring to insure propershaping of the resulting section without the formation of wrinkles,folds or scratches. A present preferred embodiment of the invention anda preferred practice thereof are illustrated in the accompanyingdrawings, although it is to be understood that the invention may beotherwise embodied and practiced within the scope of my broader claims.In the drawings:

conventional design from a single steel this application March 7 7Figure 1 is a longitudinal sectional view through the punch and die ofmy invention;

Figure 2 is a transverse sectional view thereof;

Figure 3 is a plan view of the draw ring;

Figure 4 is a longitudinal section through the tub section produced bythe apparatus of Figures 1 through 3;

Figure 5 is a view similar to Figure 1 showin the apparatus for formingthe other tub section; and

Figure 6 is a side elevation of the two sections ready to be joinedtogether by welding.

I prefer to employ a so-called toggle press for forming the tubsections. As is well known, this is a form of mechanical press havingtwo slides or vertically movable members adapted to operate in apredetermined succession. Since the construction of presses of thischaracter is well known, it is not herein illustrated nor described. Itis sufficient to state that the press has a work-supporting table in theform of a bolster adapted to support the dies through which the sheet isdrawn, and at least two vertically movable slides adapted to operate insuccession.

A bottom spacer In, which is a box-shaped casting open at the top andbottom, is adapted to rest on the bolster. The plane of the uppersurface thereof is indicated by the line H. A draw ring I2 is secured tothe bottom spacer l0. As best shown in Figure 3, the draw ring issubstantially rectangular in outline and has an opening l3 thereinrounded at one end, the edge of the opening being curved at the sidesand rounded end thereof, as shown at M. The upper surface of the drawring I2 is provided with ribs, tongues or splines I5 extending along thesides and rounded end of the opening l3. The purpose of these splineswill become apparent as the description of the apparatus proceeds.

A pressure pad I 6 is reciprocable within the bottom spacer ID by meansof pneumatic cylinders ll having pistons l8 slidable therein on whichthe pad Tests. The supply of air to the cylinders 'll 'is"controlled byany suitable form of valve, indicated diagrammatically at 19. The uppersurface of the pad I6 is concave, as shown at 20, providing a matrix toassist in shaping a metal sheet being drawn to the final contour desiredin the finished product. The pad l6, adjacent theright-hand end as shownin Figures 1 and 3, is provided with a transverse groove 2|, the purposeof which will be explained shortly.

A blank holder ring 22 is mounted on one of the slides of the press,specifically that which descends first. The slide on which the blankholder ring is supported is indicated diagrammatically at 23 in Figure2. The blank holder ring is simply a heavy plate or slab with an openingtherein conforming generally to the outline of that in the draw ring |2.The undersurface of the blank holder ring has grooves 25 therein adaptedto overlie the ribs or splines l5 on the draw ring |2. It will beapparent that if a steel sheet is laid across the draw ring I2 while theblank holder ring 22 is elevated, the cooperating ribs or splines andgrooves will serve to grip the edge of the plate, as indicated inFigures 1 and 2 and retard flow of the metal sheet therebetween as thecentral portion there'- of is pressed inwardly and downwardly.

A punch 25 is mounted on an extension 25 secured to the other slide ofthe press, viz., that which descends last. The punch 25 is shaped toproduce the desired contour of the finished bell-end tub section. Aremovable plate or shoe 21 is secured to the lower face of the punch topermit the latter to be employed for making tub sections of differentlengths. The plate 2'! has a rib or spline 28 adapted to cooperate withthe groove 2| in the pad It for the same purpose as the ribs and groovesin the draw ring and blank holder. It will be observed that the sides ofthe punch are convex outwardly, as shown at 29. The resulting tubsection has a similar contour Which is desirable in that it preventsreverse buckling such as is experienced due to expansion and contractionwhen enameling a tub having a flat or plane side wall. By curving theside wall of the tub, any buckling that may occur takes place in onedirection only and is not reversible, with the result that the enamelcoating is not fractured.

The operation of the apparatus already described will probably beapparent but will nevertheless be reviewed briefly. The toggle press isfirst operated so as to withdraw the punch 25 and the blank holder ring22. A steel sheet, such as that shown at 30, is laid across the drawring |2. The press is then operated so as to cause the blank holder ring22 to descend and grip the sheet 55 adjacent its edges. The pad I6 isthen raised to the position shown in chain lines, by manipulation of thevalve H. The press is then operated so as to cause the punch 25 todescend and progressively shape the sheet from the fiat condition,through the intermediate stage shown in dotted lines in Figure 1, to thefinal form shown in solid lines in Figure 1. As the punch descends anddeforms the sheet, the edges and central portion thereof are stretchedand deformed and there is actually some fiow of the edges of the sheetbetween th draw ring and the blank holder ring. The cooperating splinesand grooves on these parts, however, limit the inward flow of the sheetedges so that the deformation caused by the parts is largely taken up bythe elongation of the central portion of the sheet. This makes itpossible to employ as drawing stock a flat sheet having the minimumdimensions sufficient to form a tub so that the waste due to scrap iscorrespondingly reduced. At the same time the center portion of theblank is smoothly shaped to the desired contour. The pad l8 assists ingiving the proper form to the finished tub section, beiing depressedagainst the air pressure in the cylinders I! by the punch 25 as thelatter descends. The spline 28 and the groove 2| act in the same manneras the splines and grooves on the draw ring and blank holder ring, tolimit flow of the sheet longitudinally of the punch and pad. While someflow occurs, the deformation is permitted largely by the stretching ofthe center part of the sheet.

The finished tub section on removal from the draw ring has theappearance shown in Figure 4. The end of the section is then trimmed offalong the chain line 3| and the edges of the section sheared and flangedupwardly as shown at 32.

As explained in Rlodman Patent 2,114,150, the procedure in utilizing theremovable shoe 21 for the manufacture of tubs of difierent overalllengths having identical drain ends, is to change the trimming line 3|to give a bell-end blank of the desired length. Thus if the-illustratedposition of the line 3| represents the trimmed length of the bell-endblank for a 5 /2 tub, similar blanks for a 5 and 4. tub may be producedby changing the shoe 21 and shearing the blank closer to the closed endthereof. The different shoes produce blanks having difierent bottomslopes but the same depth at the open end when trimmed to differentlengths, thereby permitting the same drain-end blank to be welded to allsizes of bell-end blanks to produce finished tubs in a range of overalllengths. Since the shape of the drawn blank is determined primarily by,

the shape of the punch and its shoe, it is not necessary to change thepad it when changing the shoe 2'5, although the pad may be changed ifdesired.

The method and apparatus above described, with some slight modification,may also be employed to form the drain end of a tub such as indicated at33 in Figure 6, the finished bell end being shown at 34 in the samefigure. Figure 5 illustrates the apparatus which I prefer to employ forforming drain ends for tubs. This apparatus corresponds generally tothat of Figures 1 through 3, including a bottom spacer 35, a draw ring36 secured thereto, a pad 31 reciprocable within the spacer 35 onpneumatic cushions, a blank holder ring 38, a punch 39, and a punchextension at. The draw ring 36 is similar to that shown at l2 but is ofsubstantially U-shape in plan, being open at one end. The blank holderring is closed and the punch extension MI is recessed at 4| to receivethe inner cross member thereof. The draw ring and blank holder ring areprovided with splines and grooves 42 and 43, as already described. Thepunch 39 differs from the punch 25 so as to give the finished drain endof the tub the proper shape. The pad 31 is provided with a filler 44.The inner end of the punch, furthermore, is inclined as at 45. As aresult, the inner end of the blank or fiat sheet is bent upwardly aroundthe inclined end of the punch. This construction of the pad filler andpunch serves the same purpose as the rib 28 and groove 2| of the punchand pad of Figure 1 except that the construction of Figure 5 exerts agreater force restraining flow of the metal stock around the punch.

The operation of the modified form of apparatus shown in Figure 5 issimilar to that already described, the only difference being that thecenter portion of the inner end of the sheet of stock is bent upwardlyaround. the punch as the latter initially engages the sheet. On removalfrom the draw ring 35 after retraction of the punch and blank holderring, the tub section is then trimmed and its edges flanged as shown at33. In order to form a drain in the bottom of the drain end of the tub,I punch a hole centrally thereof. After punching a hole in thesubstantially flat bottom of the drain end, I then press the metaladjacent the hole out of the general plane of the bottom of the drainend, as shown at 46. I find that this method prevents fracture of themetal which occurred when it was attempted to deform the materialsurrounding the hole before punching the hole itself.

While it is quite possible to form tub sections in a single pressingoperation as described above, I have found that the operation can besomewhat facilitated by making it in two stages and annealing the partlyformed sections after the first operation at a temperature of between1300 and 1400 F.

After the tub sections shown in Figure 6 have been produced, they areready for joining, for example, by electric welding and, after the shoewelded joint has been ground down, the finished tub can be enameled inthe usual manner.

It will be apparent from the foregoing description that the inventionprovides a simple and highly practical method of making tubs or othersimilar receptacles from flat sheet metal by forming two sections eachin a single operation if desired, and joining them together. As beforestated, the method and apparatus disclosed make possible theaccomplishment of this result with a minimum of scrap material and dies,thus reducing the cost of the finished product.

Although I have illustrated and described but one preferred embodimentof the apparatus and practice of the method, apparatus and procedureother than that described may be employed without departing from thespirit of the invention or the scope of the appended claims.

I claim:

1. Apparatus for forming from sheet metal a blank adapted to constitutethe bell-end of a bath tub composed of two stampings, i. e., a bellendand a drain-end, connected by a welded joint circumferentially of thetub, said blank including a rounded, sloping bottom, sides and arounded, sloping end, the other end being open, said apparatuscomprising a draw ring having an elongated opening therein rounded atone end, an elongated punch reciprocable through said ring, the end ofsaid punch cooperating with the rounded end of the ring being similarlyrounded and sloping downwardly toward the other end of the punch, thebottom of the punch proper being substantially flat over the greaterportion of its length, a shoe removably secured to and covering thegreater portion of the fiat bottom of the punch proper, said shoe havinga bottom face curved transversely of the punch and sloping downwardtoward said other end thereof, and a yieldable pad below said punchhaving a matrix therein shaped to receive said snugly with a thicknessof metal therebetween and thereby form the rounded, sloping bottom ofthe blank.

2. Apparatus for forming from sheet metal a blank adapted to constitutethe bell-end of a bath tub composed of two stampings, i. e., a bell-endand a drain-end connected by a welded joint circumferentially of thetub, said blank including a rounded, sloping bottom, sides, and arounded, sloping end, the other end being open, said apparatuscomprising a draw ring having an elongated opening therein rounded atone end, an elongated punch reciprocable through said ring, the end ofsaid punch cooperating with the rounded end of the ring being similarlyrounded and sloping downwardly toward the other end of the punch, thebottom of the punch proper having a shoe-seating surface over thegreater portion of its length, a shoe removably secured to and coveringthe greater portion of the shoe-seating surface of the punch proper,said shoe having a bottom face curved transversely of the punch andsloping downward toward said other end thereof, and a yieldable padbelow said punch having a matrix therein shaped to receive said shoesnugly with a thickness of metal therebetween and thereby form therounded, sloping bottom of the blank.

HAROLD W. CLARK.

